Overall the site looks very nice. I understand the reasoning behind the coloring but I would try to change the yellow and green backgrounds to white if possible in order to make it easier for your viewers to read. They could be on a number of different screen sizes and this may strain their eyes too much.

If sales are good, maybe there's no need but that would be my main suggestion.

A few other things:

Add the SSL site seal to let more people know that your site is safe. Also, there are pages including the account page that are calling insecure links and it prevents the browser from displaying the green padlock.

You may also want to consider putting payment logos in a sidebar or in the footer just to inform the shoppers even more of the types of payments you accept.